Dishwasher appliances generally include a tub that defines a wash chamber. Rack assemblies can be mounted within the wash chamber of the tub for receipt of articles for washing. During wash and rinse cycles, spray assemblies within the wash chamber can apply or direct wash fluid (e.g. various combinations of water and detergent along with optional additives) towards articles disposed within the rack assemblies in order to clean such articles.
Multiple spray assemblies can be provided including e.g., a lower spray arm assembly mounted to the tub at a bottom of the wash chamber, a mid-level spray arm assembly mounted to one of the rack assemblies, and/or an upper spray assembly mounted to the tub at a top of the wash chamber. Other configurations may be used as well.
One limitation of many currently known spray arm assemblies is the geometry of the spray arm assemblies relative to the geometry of the wash chamber. Most known spray arm assemblies utilize a generally circular geometry. For example, an arm of a spray arm assembly may rotate in a circle, and jets or apertures defined in the arm may emit wash fluid from the arm in this circular pattern. Each jet emits fluid in a constant direction from the associated arm during rotation, so that the locations reached by the wash fluid are predictable and limited. Further, the cross-sectional interior geometry of most currently known dishwasher appliance wash chambers is square or rectangular. Accordingly, the corners of such wash chambers, and the articles located therein, may not be sufficiently reached by wash fluid. These limitations can result in articles not being properly cleaned during operation of the dishwasher appliance.
Although certain known spray assemblies attempt to provide better spray coverage by increasing the number of spray arms or altering the spray action, these assemblies lack versatility in their manner of operation and are often inefficient in terms of energy and water usage. For example, these spray assemblies may only operate all spray arms simultaneously and/or at high flow rates, lack spray arms for dedicated zone cleaning, and have poor cleaning efficiency, thus requiring the use of excess water and energy.
Accordingly, improved spray arm assemblies and associated dishwasher appliances are desired in the art. In particular, improved spray arm assembly designs which increase the coverage of the wash fluid emitted therefrom would be advantageous. Spray arm assemblies that can also be operated in different modes, e.g., to operate multiple arms synchronously or asynchronously, would be particularly beneficial.